This invention pertains generally to the generation of models of physical objects for display by a data processing system and more specifically to generating a computer model of an actual city for use in generating a cityscape of the city.
A mathematical representation, or model, of a physical object is often very useful. Such models can be used to simulate actions or relating to the physical object. This is particularly helpful when the actions, if actually performed, would damage the actual physical object, or if the physical object is unavailable for the proposed actions.
One type of model is a three dimensional image of a physical object. Such models are used to generate views of the physical object for display by a data processing system. Such models may be used instead of digitized photographs or other more immediate representations of the actual physical object for a variety of reasons. One reason is that models can be used to generate a view of a physical object from different viewing location or under any lighting condition. This ability is useful in, for example, video games. In video games a person playing the game often virtually moves through a simulated physical environment, with the person's virtual position within the environment changeable with respect to objects in the environment and the environment as a whole. As the person moves through the simulated environment, portions of the model may be retrieved by the video game and used to generate a view of the environment that corresponds to the person's position and view point in the city. This creates an illusion that the person is actually in the in the environment depicted by the model.
Simulated environments may be developed by software developers or artists who create each element or object in the model manually. While this method may result in a detailed model capable of being used to generate detailed and realistic views of an environment, the method is time consuming. Alternatively, systems for creating environments may rely on automatically generating features within an environment by automated rules. While these rule-based systems may be able to rapidly generate a model, the resulting model may lack the detail and randomness that give the impression that the model is a representation of an actual environment. In addition, both types of systems fail in modeling an environment of an complexity, such as an actual city. The manual systems or simply too laborious for an artist or software developer to use in creating a detailed model of an actual city and the rules used in rule-based systems are simply incapable of capturing the complexity of an actual city.